1. Field of the Invention
The present invention relates to a control device of an internal combustion engine.
2. Description of the Related Art
In an internal combustion engine, to obtain the optimal output and to effectively purify exhaust gas, the amount of air filled into a cylinder (cylinder filling air) must be found. For this purpose, normally, the amount of air taken into the internal combustion engine per unit time (intake air flow rate) is found. As the method of finding this intake air flow rate, the method is known of providing an air flow sensor in the intake passage and using that air flow sensor to directly find the intake air flow rate (for example, see Japanese Unexamined Patent Publication (Kokai) No. 2002-97994).
However, depending on the internal combustion engine, sometimes there are a plurality of intake passages upstream of the throttle-valve. Japanese Unexamined Patent Publication (Kokai) No. 2002-97994 only covers the case where there is a single intake passage upstream of the throttle valve. It does not describe the method of finding the intake air flow rate for the case of a plurality of intake passages.